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03 DTS Flushed cooling system put in radiator cleaner through heat on full blast ran the car for 45 minutes flushed system replaced hoses and thermostat then fan starting working intermittenly once it came on it worked perfect so I checked plugs on fan motor touched it it started working again for a day or two then same thing. Replaced Male side of plug no good to replace female on fan side you have to change the motor. Replaced with retrofit motor worked only one speed now not at all compressor cycles on but not fan or Defroster either on auto or manual. Any suggestions Thanks.

 

                                                                                                                                                                                                                                                            Frank 

 

 

 

 

 

 

 

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With the A/C on is the fan running?

If the cooling fan is not running with the A/C on I would check the relay/s. I think the relays are mounted on the radiator core support between the two fans. There should be three relays.

If the A/C is not on, the cooling fans are temperature controlled and will come on when engine temp reaches 220F-230F and shut off once the coolant temp cools. I don't have a 2003 manual so I may be off a few degrees.

Since the NStar is VERY hard to get the air out of, set the heat to 90 and make sure the air is hot coming out of the floor outlets. If it is not the coolant temp reading the computer is receiving could be skewed by the air in the system. coolant temp sensors only work when submerged in fluid, the accuracy of the sensor is nil when air is around it.

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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The very first thing you need to do is check for codes and report them here.  If you do not know how to extract them through the dash let us know.   As OCT notes the fans operate differently based on whether the AC is on or off cycling at different temps and actions.

Report all codes, this is an example of the type of codes the cooling fans can set

DTC P0480 Cooling Fan Relay 1 Control Circuit

DTC P0481 Cooling Fan Relay 2 Control Circuit

DTC P0482 Cooling Fan 3 Control Circuit Malfunction

DTC P0483 Cooling Fan Rationality Check Malfunction

DTC P0484 Cooling Fan Circuit Over Current

DTC P0485 Cooling Fan Power/Ground Circuit Malfunction

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Hey Guys I meant the Blower for the A/C Heater climate control Figured it out with research from parts supplier who got the Blower motor There is also a rheostat that is not on the Blower motor it is under the dash also above the Blower motor. He told me this is a common problem. Thanks for all the input it is appreciated.

                                                                                                                                                                       Frank  

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BIG DIFFERENCE!

There is no resistor (or rheostat) on these cars, the fan controller goes bad.  The fan is powered by PWM pulsed width modulation so you cant test it by powering it up or testing for voltage.

If you have a bad engine temp sensor that could cause it to not start possibly.

Post your codes!

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I think he's talking about the power module Mike but it sounds like he has it fixed now. 

Most parts guys think the power module has everything in it including a dish washer, clothes dryer and the ....... sink. ;) 

It does have a heat sink though :lol:

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Haha, how did you go from rheostat to power module?  :D Although rockauto has this part >>  Blower Motor Control Module / Resistor

This would be the first time in all the time I am here that a part outside the blower motor itself is responsible for the blower not running!   Usually, the on board motor controller is damaged by EMF from the ignition wires.  There is no resistor on this system.

This would be a new one.  I hope the OP comes back with more details. 

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I replaced a LOT of them. I made a connector wired through a rheostat to plug into the blower motor and I could apply 12V to it. If it worked okay = replace module..

I gave it to my brother to use and he lost it for me :(

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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55 minutes ago, OldCadTech said:

I replaced a LOT of them. I made a connector wired through a rheostat to plug into the blower motor and I could apply 12V to it. If it worked okay = replace module..

I gave it to my brother to use and he lost it for me :(

Never lend tools!  :ph34r::P

I am very surprised we never had module issues before, I hope KHE sees this.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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The module does have a resistor in it to control blower speed.

My brother is off the tool lending list without direct adult supervision :D

The pic is from a 97 but GM just moves em around, they get very hot so they are in the air stream from the blower motor..... Your caddy has one too... :P

zjlimited_723.gif

THERE IS ALWAYS ENOUGH TIME TO DO THE JOB RIGHT - THERE IS NEVER ENOUGH TIME TO DO THE JOB AGAIN !!!

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Incredibly we have NEVER had one of these go bad, it has always been the motor!   KHE?

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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On the 2003 DTS....the blower is inside the car...with control module...#2. Not like the older ones with the blower out under the hood.

 

2003blower.jpg

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Thanks Logan

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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